Various governmental test standards have been developed for determining the acceptability of flame-retardant fabrics. A so-called "horizontal test" comprises clamping a treated textile material, held in the horizontal position, to a piece of lens paper and impinging a flame against the textile. According to this test, the textile is deemed satisfactory if the lens paper is not scorched.
A more stringent standard was adopted in the so-called "vertical test" (Department of Commerce DOC FF 3-71 Standard for Children's Sleepwear of 0 to 6X sizes). In this test, a piece of textile material is held in a vertical position while the bottom edge of the piece of material is exposed to a gas flame for three seconds. The flame retardant characteristics of the material are deemed acceptable (1) if either five samples of the textile burn for no more than a total of seven inches (average of five samples) or flame for no longer than ten seconds; (2) if no sample burns for 10 inches; and (3) if the treated textile meets the aforementioned requirements after fifty washes, or at the time at which the textile product is no longer useful.
A typical fabric which has met with substantial commercial success as a material for blankets and sleepwear is that disclosed in U.S. Pat. No. 3,528,874 granted on Sept. 15, 1970 to Francis T. Spencer. This patent sets forth a construction wherein a reinforcing ply of material is secured on one or both of its sides to a polyurethane foam layer(s) to the exposed surface(s) of which flock is adhered.
In an effort to reduce the flammability characteristic of fabric of the type disclosed in U.S. Pat. No. 3,528,874, it is known to include a flame-retardant in the adhesive which joins the flock to the foam substrate. However, when applicant and his assignee have experimentally mixed flame-retardant compositions with the flock adhesive in sufficient quantities to permit the fabric to pass the vertical flame test, the resultant product has proven unsatisfactory. More particularly, the adhesive has either not retained its capacity to bond the flock to the foam substrate, or the product has become too stiff to possess the drapeability and softness characteristics required for use as blankets and sleepwear. The latter problem cannot be easily remedied by inclusion of plasticizer into the flame-retardant flock adhesive system since plasticizers may promote fabric yellowing, foam decomposition, adhesive incompatibility or migrational problems.